Isolation of Circulatory Influence in HSG
Abstract
The respiratory and circulatory function in chickens exposed to high sustained Gz (HSGz), greater that 6 G for 15 seconds is reported. In mammals, such treatment induces ventilation perfusion inequalities and pulmonary shunts which limit tolerance. Chicken lungs undergo little distortion during acceleration exposure because of their inelastic, noncompliant nature. Acceleration tolerance time (T(t), min) for cocks exposed to +6, +8, +10, and +12 Gz is hyperbolically related to the field strength (G): T(t) = (240.15/G) - 18.61. This indicates that the product of exposure time and field intensity is constant over the range examined. Chickens, unlike mammals, have near normal Pa02 and PaCo2 during Hsgz exposure. Forced ventilation of centrifuging chickens with oxygen increased pa02, a response not found with mammals. Ventilation of one lung with air at 1 G produced near normal pa02 and PaCO2, but in HSGz it gave low Pa02 as compared to spontaneously breathing mammals. Ventilation did not extend all tolerance times, indicating that circulatory impairments are factors limitating acceleration tolerance. Expored PC02 during oxygen down to zero for several seconds; after HSG, expired PCO2 increased, indicating that oxygen debt and metabolismperfusion inequalities occurred during HSGz. (AW)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1980
- Accession Number
- ADA216815
Entities
People
- A. H. Smith
- R. E. Burger
- S. C. Walgenbach
Organizations
- University of California, Davis